As computer-based systems, appliances, automated teller machines (ATM), point of sale terminals and the like become more prevalent, the ease of use of the human-machine interface is becoming more important. Such interfaces should operate intuitively and require little or no user training whereby they can be used by virtually anyone. Many conventional user interface devices are available on the market, such as key boards, mouse, joysticks, and touch screens. One of the more intuitive and interactive interface devices known is the touch sensitive panel, which can be a touch screen or a touch pad. A touch screen includes a touch sensitive input panel and a display device, and provides a user with a machine interface through a panel sensitive to the user's touch and displaying content that the user can see and then “touch.”
Conventional human-machine interfaces, such as keyboard, voice, and touch screen, typically require visual assistance or look during the interface operation. For instance, when a user inputs his or her selection(s) over a touch screen, the user needs to look and/or identify the location to be touched. Also, when a user operates a mouse, the user needs to see the movement of an icon on the screen before he or she can press the click button.
A problem associated with the conventional human-machine interfaces is that sometimes visual assistance is not available during the operation of human-machine interface. For example, a truck driver or a pilot often needs to keep his or her vision on driving or flying, and thus, can not look at the interface device during an input/selection operation. Also, a worker may not be able to hear audible instructions in a noisy environment.